…dd tests

…nd add tests

With SmoothingModels and CandidateGenerator now beeing able to be serialized via NamedWritable infrastructure, PhraseSuggestionBuilder can now properly delegate read/write and equals/hashCode to their implementations. Also adding randomization of smoothing model and candidate generators to tests.

Added the term suggestion builder's serialization/deserialization and
equals/hashCode methods.

Refactored the term suggestion builder for the query refactoring effort

Ensures that the clients' serialization of the sort and string edit
distance enumeration values as upper case are correctly normalized
when parsing the incoming JSON.

For the ongoing search refactoring (#10217) the PhraseSuggestionBuilder
gets a way of parsing from xContent that will eventually replace the
current SuggestParseElement. This PR adds the fromXContent method
to the PhraseSuggestionBuilder and also adds parsing code for the
common suggestion parameters to SuggestionBuilder.

Also adding links from the Suggester implementations registeres in the
Suggesters registry to the corresponding prototype that is going to
be used for parsing once the refactoring is done and we switch from
parsing on shard to parsing on coordinating node.

This adds parsing from xContent to PhraseSuggestionBuilder and changes properties of PhraseSuggestionBuilder to using default values form PhraseSuggestionContext where possible.

 Conflicts:
	core/src/main/java/org/elasticsearch/search/suggest/phrase/PhraseSuggestionContext.java

Add fromXContent method to SuggestBuilder

Feature term suggester xcontent

 Conflicts:
	core/src/main/java/org/elasticsearch/action/suggest/TransportSuggestAction.java
        core/src/main/java/org/elasticsearch/search/suggest/SuggestParseElement.java
	core/src/main/java/org/elasticsearch/search/suggest/SuggestionSearchContext.java
	core/src/main/java/org/elasticsearch/search/suggest/phrase/PhraseSuggester.java

…nto suggester-wiring-refactoring

error message.

Test failures showed problems with passing down
the same collate parameter map reference from the
phrase suggestion builder to the context where.
This changes the collate parameter setters to
make a shallow copy of the map passed in.

Fixing some tests and compile problems in reindex module

Change internal representation of suggesters

 Conflicts:
	docs/reference/migration/migrate_5_0.asciidoc